From: Sandy King (sanking@clemson.edu)
Date: 07/08/03-08:12:22 PM Z
Last summer I considered building a large vacuum frame, either one of
the thpe described by Dave, which is very similar to a design in
David Scopick's book on gum bichromate, or one based on a design
constructions at an unlinked page on the Bostick and Sullivan site.
However, I never got around to either project, and am glad now that I
did not because I eventually bought a very large (44X36") unit on
Ebay for a pittance, probably less than I would have spent on
building a unit of this size.
Lots of pre-press equipment of this type is selling for a fraction of
its former cost at this time. Look in your local market or on ebay
and you will find some incredible bargains in printing equipment.
However, let me point out that a good contact printing frame is still
a very useful piece of equipment. I can take my Great Bassin outside
and make salted paper prints in direct sun, with wonderful sharpness,
plus the hinged back is a very useful feature with many processes. No
way to look at the progress of exposure of the image with a vacuum
frame, or with a glass plate sandwich for that matter. And for making
test exposures I always use a contact printing frame, just placing it
on top of the glass of the vacuum easel. This is neat with long tests
because it avoids the use of the vacuum pump, which can be a bit
noisy.
Sandy King
>My vacuum frame was constructed using a 20x24" sheet of 3/4" plywood with a
>matching piece of pegboard laminated to it. I used a router to cut a series
>of shallow interconnecting grooves (air channels) into the plywood prior to
>glueing the pegboard on. The grooves lie directly underneath the holes in
>the pegboard. A tube glued into the edge of the plywood intersects the air
>channel, providing an easy way to attach a vacuum. I used thick
>construction adhesive (available in a tube and applied with a caulking gun)
>to ensure a tight seal between pegboard and plywood. The pegboard was
>sanded smooth and painted flat black. A 20x24" sheet of polyester is taped
>to one edge of the frame. To use, I lift up the polyester, place the
>neg/paper underneath and turn on the vacuum. Within seconds, the polyester
>is pulled tight against the pegboard, providing intimate contact between
>negative and paper.
>
>The vacuum frame is hinged onto the edge of a wooden box that contains a
>bank of UV fluorescent lights. The exposure unit is bolted vertically onto
>a wall in a position that's very convenient for loading and use, without
>taking up valuable counter space.
>
>I haven't had problems with the pegboard holes being too large. An insert
>of stiff, open-cell foam might be a good alternative to using pegboard. If
>you think about it, there are many different ways to construct a vacuum
>frame. All it takes is a good design and skill using power tools.
>
>The question of whether the polyester overlay degrades image quality has
>come up in the past. It does not. I'm using "Kleerbase", a product
>marketed to the graphic arts industry.
>
>Best regards,
>Dave Rose
>Big Wonderful Wyoming
>
>----- Original Message -----
>From: "Vincent Dobson" <manitec@bellsouth.net>
>To: <alt-photo-process-l@sask.usask.ca>
>Sent: Tuesday, July 08, 2003 7:15 AM
>Subject: RE: contact printing frames
>
>
>>
>>
>>
>> <:)-----Original Message-----
>> <:)From: Dave Rose [mailto:cactuscowboy@bresnan.net]
>> <:)My homemade vacuum frame was assembled in an afternoon. It was easy to
>> <:)build and inexpensive. With it I can print tack-sharp contact
>> <:)prints
>>
>> Hi,
>>
>> Good news, but just two questions?
>>
>> How do you (or can you) view to check development without losing
>> registration?
>>
>> And --- How did you drill all those little holes? Did you use something
>> stock for this. I would think pegboard holes would be too large and too
>> few.
>>
>> Thanks
>>
>>
>>
>>
>>
>> Vince Dobson
>> Visions In Nature
>> www.VisionsInNature.com
>>
>>
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